Gas Laws Standard Temperature and Pressure (STP) Standard temperature: 0?C or 273 K Standard pressure:1 atm, 760 mm Hg, or 101.3 kPa Boyle?s Law The pressure of a dry gas is inversely proportional to its volume if the temperature is held constant. Inverse Proportion two terms related so that, if one term increases, the other term decreases Boyle?s Law P V , PV = k P1V1 = P2V2 As pressure increases, volume decreases. 6 Chemistry textbook, p. 250 7 Chemistry textbook, p. 250 P1V1 = P2V2 Sample Problem 1 A sample of gas occupies 352 mL at a pressure of 3.17 atm. If the P is reduced to 1.24 atm, what volume will result? (3.17 atm)(352 mL) = (1.24 atm)V2 900 mL = V2 A sample of gas occupies 200 mL at a P of 2.15 atm. If the P is reduced to 1.25 atm, what is V2? 344 mL 537 mL 98 mL 89 mL